Preparation of zerovalent nickel complexes from elemental nickel

ABSTRACT

Zerovalent nickel complexes of the types Ni(MZ3)4 and Ni(MZ3)2A; wherein M is P, As or Sb, Z is R or OR, R is an alkyl or aryl radical having up to 18 carbon atoms and may be the same or different, and at least one Z is OR, A is a monoolefinic compound having 2 to 20 carbon atoms, the R radicals of a given MZ3 of Ni(MZ3)2A preferably being so chosen that the ligand has a cone angle of at least 130*; are prepared by reacting elemental nickel with the MZ3 ligand at a temperature in the range of 0*C.-150*C. in the presence of a halogen containing derivative of MZ3 as a catalyst. A more rapid reaction is realized by carrying out the preparation in an organonitrile solvent.

United States Patent Shook, Jr. et al. Sept. 2, 1975 [56) PREPARATION OF ZEROVALENT NICKEL 3,642,658 2/1972 Allum et al 252/431 P COMPLEXES FROM ELEMENT AL NICKEL 3,671,560 6/ I972 Fahey 260/439 R 3,766,233] 10/1973 Gosser et a]. 260/439 R Inventors: Howard k, Jr-, g 3,808,246 4 1974 Fahey 260/439 R John B. Thompson, Wilmington, Primary Examiner-Arthur P. Demers [73] Assignee: E. I. Du Pont de Nemours and Company, Wilmington, Del. [57] ABSTRACT 22 Filed; 13, 1973 Zerovalent nickel complexes of the types Ni(MZ and Ni(MZ A; wherein M is P, As or Sb, Z is R or [21] Appl' 424364 OR, R is an alkyl or aryl radical having up to 18 car- Related Application D bon atoms and may be the same or different, and at least one Z is OR A is a monoolefinic compound hav- S [63] f7$ of er No 371501 June ing 2 to 20 carbon atoms, the R radicals of a given MZ of Ni(MZ A preferably being so chosen that 52 us. c1...... 260/439 R; 252/431 P; 252/431 N; the ligand has a cone angle of at least 130; are P 26O/4653; 26O/346 8 pared by reacting elemental nickel with the MZ li- 51 1m. 01. 0071 15/04 gand at a temperature in the range of [58] Field of Search 260/439 R, 346.8 the Presence of a halogen Containing derivative of MZ as a catalyst. A more rapid reaction is realized by [56] References Cited carrying out the preparation in an organonitrile sol- UNITED STATES PATENTS Vent 3,631,191 12 1971 Kane Ct al 260/439 R 14 Claims, N9 Drawings wa -wk. w.

PREPARATION OF ZEROVALENT NICKEL COMPLEXES FROM ELEMENTAL NICKEL CROSS REFERENCE TO RELATED APPLICATION This is a continuation-in-part of patent application Ser. No. 371,501, filed on June 19, 1973 by Howard E. Shook. Jr. and John B. Thompson, now abandoned.

BACKGROUND OF THE INVENTION This invention is concerned with preparation of Zerovalent nickel complexes. It is well known that the Zerovalent nickel complex, nickel carbonyl. can be pro duced in high yield by conducting carbon monoxide over finely-divided nickel in a carefully controlled temperature range. As reported in the literature L. D. Quin, .I.Am. Chem. Soc, 79, 3681 (1957) reaction of CH PCl with elemental nickel gives a good yield of the complex Ni(CI-I;,PCl-;) but phosphorus compounds such as PCL, and C,;H -,PC1 were observed not to react with elemental nickel. Similarly aryl-substituted phosphorus compounds such as o-C I-I [P(C H C H [P(C,;H and o-C,;H [P(C H,-,) have been reported to give only low yields of Zerovalent nickel complexes on reaction with elemental nickel [Chatt et al., J. Chem. Soc. 1378 (1960); 5504 (1961)].

Because of the growing interest in Zerovalent nickel complexes, especially those of aromatic phosphorus compounds as catalysts in oligomerization and hydrocyanation reactions, an improved method for the systhesis of these valuable complexes has been sought.

SUMMARY OF THE INVENTION An improved process has been found for the synthesis of Zerovalent complexes of nickel with a ligand such as MZ wherein M is P, As or Sb, Z is R or OR and R is an alkyl or aryl group having up to 18 carbon atoms and the Rs of a given ligand may be the same or different, and at least one Z is OR. The process comprises reacting the ligand with elemental nickel, preferably in finely-divided form at a temperature in the range of C.l50C., preferably 25l00C., in the presence of at least mpm (moles per million moles), preferably at least 50 mpm, based on the ligand, of a catalyst of the formula (RO) .R",,MX wherein M is as defined above, R and R" are alkyl or aryl radicals having up to 18 carbon atoms, may be the same or different, .r and 3 have a value of 1-2, y is 0 or 1 and the sum ofx, and is 3 and wherein X is a halide of the group consisting of chloride, bromide and iodide.

The reaction can be carried out using an excess of the ligand as a solvent. A more rapid reaction rate is realized if an organic mononitrile or dinitrile is used as solvent. Typical organic nitriles which can be used include acetronitrile, acrylonitrile. 3-pentcnenitrile, methylglutaronitrile and adiponitrile. Any organic nitrile which is liquid under the reaction conditions can be used. Cosolvents which are compatible with the organic nitrilcs such as benzene. toluene, xylenes. cresols. cyclohexane or dioxane can also be employed. The reaction is carried out batch-wise or continuously at atmospheric or superatmosphcric pressure in an inert atmosphere such as nitrogen, carbon dioxide, or other inert gas such as helium. neon, argon or kypton.

One type of Zerovalent nickel complex that can be made by the process of this invention is that of the formula Ni( MZ wherein MZ is as defined above. Typical ligands of the formula M2 include the group conand A is a monoolefinic organic compound with no other carboncarbon unsaturation and having from 2 to 20 carbon atoms. It is preferred that the R radicals of a given M2 ligand be so chosen that the ligand has a cone angle of at least and that the carbon-carbon double bond of A be conjugated with a strong electronegative radical such as carbonyl or nitrile, as in maleic anhydride, fumaronitrile or acrylonitrile. The cone angle as referred to above is determined as described by C. A. Tolman in J. Am. Chem. Soc., 92 2956 (1970). Olefins such as ethylene, propylene, butylene and the like, as well as the olefinic compounds noted above, can be used. Phosphorus ligands fulfilling the requirement of having a cone angle of at least 130 include tri-o-tolyl phosphite, tri-( 2,5-xylyl)phosphitc, tri- (2,4-xylyl)phosphite, tri-o-phenylphenyl phosphite, diphenyl phenyl phosphonite, di-o-tolyl phenyl phosphonite and phenyl diphenyl phosphinite. Preferred Zerovalent nickel complexes include Nil P- 4 s):sl2I 2 4l- I ts -i :il2I 4 2 :i* l l G 4 3)IIZI -I 2 2 l 11nd l Under hydrocyanation conditions in the presence of compounds to be hydrocyanated such as 3- pentenenitrile (3PN) these complexes can be readily pending on whether the 3PN is coordinated with Zerovalent nickel through the nitrile or olefin moiety.

Zerovalent nickel complexes of the type Ni(MZ ,A or mixtures of types Ni(MZ;,)- A and Ni( M2 can be produced by the process of this invention when MZ is a phosphorus ligand such as mixed tri-, metaand paratolyl phosphite wherein the cone angle is less than 130. With these complexes also it is preferred that the carbon-carbon double bond of A be conjugated with a strong electronegative radical such as carbonyl or nitrile.

Zerovalent complexes of the types described above wherein the R radicals of a given M2 ligand are different can also be produced by the process of this invention. Illustrative ligands of this type include such phosphorus ligands as di-o-tolyl phenyl phosphite, di-o-tolyl p-tolyl phosphite, di-o-tolyl m-tolyl phosphite, o-tolyl diphenyl phosphite, o-tolyl di-p-tolyl phosphite or otolyl di-m-tolyl phosphite wherein the cone angle of the given ligand is greater than 130 as well phosphorus ligands wherein the cone angle is less than 130 such as 3. diphenyl p-tolyl phosphite, diphenyl m-tolyl phosphite, phenly di-p-tolylphosphitc or phenyl di-m-tolyl phosphite. Preparation of zerovalent complexes of this type are illustrated in Example 54.

The reaction can be carried out with a stoichiometric amount of nickel with respect to the phosphorus ligand or a deficiency or excess of nickel can be used. In general, it' is observed that a more rapid reaction rate is realizedwhen an excess of nickel is employed.

As noted above, it is preferred that the nickel be in finely-divided form so as to provide a high surface area for reaction. Suitable nickel sources for this purpose include those made available by International Nickel Company (INCO) under the designations Chemical Grade and Specimen Nos. 123. 128 and 255. Raney nickel or other forms of elemental nickel such as that produced from a hydrogen reduced nickel compound can be used. Aswill be apparent to one skilled in the art, the surface of the nickel is preferably clean, i.e., free of oxygen or other material.

It is preferred to carry out the reaction using an organic nitrile as a solvent. Best results are obtained with a'mole ratio of organic nitrile to nickel of at least 0.5. A considerable excess of the organic nitrile can be used, the main consideration being one of economics. Ordinarily the amount would be in the mole ratio of The catalyst compounds (R'O),R" .,MX can be preformed or they can'be prepared-in situ by reaction of anappropriate ligand, a ligand having at least two ROM linkages, with a suitable halide source as an initiator such as a halide or alkyl-substituted halide of phosphorus, arsenic or antimony such as CH;,PCI. CH},AsClg or CH SbCIL an appropriate metal halide, elemental halogen such as chlorine. bromine or iodine or the corresponding hydrogen halide or thionyl halide. Suitable metal halides for this purpose include those of Cr, Ni, Ti, Cu. Co, Fe, Hg, Sn, Li, K, Ca, Ba, Sc, Ce. V, Mn, Be, Ru, Rh, Pd,Zn, Cd, Al, Th, Zr, and Hf. The halide can be chloride, bromide or iodide. Particularly suitable halidesources include PX TiX ZrX I-IfX and HX where X is chloride. bromide or iodide. Mixtur'es of two or more initiators or catalyst can be used in carry'ing out the reaction.

The zerovalent nickel complexes produced by the process of this invention are especially useful as catalysts, in particular, for the hydrocyanation of olefins.

DESCRIPTION OF PREFERRED EMBODIMENTS The invention is more fully illustrated in the examples to follow. In the examples to be described below the reactions are carried out'in an inert atmosphere such as nitrogen in a 300 ml. flask fitted with magnetic stirrer, condenser and thermometer. The apparatus was first purged with dry nitrogen and the reactants under a nitrogen blanket were charged to the flask and continued under nitrogen during reaction. The liquid reaction products were recovered from the flask under vacuum through a Buchner funnel attached to the bottom of the flask and analyzed for total nickel and for zerovalcnt nickel. Total nickel can be determined by dissolving the sample in aqueous solvent after fusion with phosphorus pyrosulfitc or by dissolving the sample directly in methanol and thereafter determining nickel by atomic absorption spectroscopy. The zerovalcnt nickel can be determined by gel permeation chromatography. The zerovalent nickel complexes have a much higher molecular weight (and size) than any other component in the reaction medium. This fact forms the basis for the separation of the complexes from low molecular weight species by gel permeation chromatography on a crosslinked polystyrene gel. Quantitative determination is carried out using a previously determined calibration plot for the complex. For certain complexes such as Ni(MZ A, the analysis is carried out after reaction with carbon monoxide to form the more stable complex Ni(MZ,,) (CO).

Examples l 4 illustrate the preparation of zerovalent nickel complexes of the type Ni(PZ with Example 4 depicting in situ preparation of the catalyst for the reaction. The preparation of complexes of the type Ni(PZ )2A is illustrated in Examples 5-8 as well as the in situ preparation of the catalyst for the reaction, with preparation of the catalyst in particular shown in Examples 9-11. Preparation of complexes embracing both Ni( P2 and Ni( PZ A types is shown in Example l2.

EXAMPLE 1 TETRAKIS(TRI-M & P-TOLYLPHOSPHITE)NICKEL(O) A. Three grams of finely-divided nickel powder (INCO Chemical Grade), 40 grams of 3-pentenenitrile, grams of undistilled mixture of metaand paratritolyl phosphite containing an estimated 1 190 ppm of (m & pCH -;C ;H O) PCI based on weight of the tritolyl phosphite, which was produced during manufacture of the tritolyl phosphite, were weighed out and transferred to the reator under dry nitrogen. The nitrogen purge was maintained while the reaction mixture was rapidly heated to C. and maintained at that temperature for four hours with stirring. The heating was stopped and the reactor was cooled to bring the temperature of the reaction mixture to about 50C. The ni' trogen purge was stopped; the reaction product withdrawn from the reactor through the Buchner funnel weighed 1 19-. g. Concentration of Ni[POm & p-C,, H CH was 45.3% corresponding to a conversion of nickel powder to zerovalent nickel in solution of 72%.

B. The reactants described above. except for omission of 3-pentenenitrile, were reacted at 100C. for four hours. The filtered product weighed 76.63 g. Concentration of Ni[ P( O-rn & p-C H CH,,) was 3.9%.

EXAMPLE 2 TETRAKIS(TRl-M & P-TOLYL PHOSPHITE)NICKEL(O) Following the procedure of Example 1, the same re actants along with 0.2 g. of NiCl and 0.2 g. of ZnCl were reacted at 80C. for four hours. The filtered product weighed 1 19.69 g. Concentration of Ni[P(Om & pC.,H ,CH was 47.4%, corresponding to -TET- RAKIS('TRIPHENYL of elemental nickel to soluble zerovalent nickel of 76%.

EXAMPLE 3 TETRAKIS(TRI-M & P-TOLYL PHOSPHITE)NICKEL(O) The reactants described in Exammple 1, except for substitution of acetonitrile for 3-pentenenitrile, were reacted at 78C. for four hours. The filtered product weighed 113.42 g. Concentration of Ni[P(Om & pC,;H ,CH was 51.8%. corresponding to 78% conversion of elemental nickel to soluble zerovalent nickel.

EXAMPLE 4- ETRAK1S(TR1PHENYL PHOSPH1TE)NICKE1(O) to a oneliter flask fitted with a highspeed stirrer and addition funnel and previously evacuated and flushed with nitrogen there was introduced 1.5 gram:of Randy nickel slurry (50% Ni in water). The flask .was evacuated (0.2 mm, 40C., 20 minutes) to remove water after which 68 ml. of re'distilled triphenyl phosphite was added, the reaction mixture was blanketed with dry nitrogen and brought to 1 C. over aperiod of about 35 minutes and held at a temperature of 110120C. for two hours. To the mixture therc was added 100 ml. of 3-pentenenitrile. the mixture was reheated to 1 l0 .120C. and held in that range for two hours. The reaction mixturewas cooled to roomtemperature and examined. No evidence of reaction was observed.

About 0.5 g. of substantially anhydrous zinc chloride wasadded to the reaction mixture, after which it was heated to l 10125C. under nitrogen for three hours, then cooled to room temperature. The liquid product was decanted off the nickel powder and placed-in bot:

' tle and blanketed with nitrogen. Within about minutes white crystals of EXAMPLE 5 MALEIC ANHYDRIDE [BlS-(O-TRlTOLYL PHOSPHITE)]N1CKEL(O) This example illustrates the preparation of a zerovalent nickel complex from a bulky ligand; tri-o-tolyl phosphite. (cone angle 141) in the added presence'of an olefinic compound, maleic anhydride. and further illustrates the in situ preparation of the required catalyst for carrying out the reaction.

An acetonitrile ml) solution of 4.9 g. maleie anhydride, m1. tri-o-tolyl phosphite (o-TFP). 3' g. nickel powder. and 0.13 g. TiCl was stirred under nitrogen for 20 hours at 65C. The reaction flask was cooled to 0C. for two hours, and the crude complex was filtered off. The complex was dissolved in 50 ml. hot toluene and filtered through a medium frit. Thereafter the complex was precipitated by addition of 200 ml. of methanol, the residue after filtration was washed well with toluene to yield 27.2 g. of purified complex Nil P(O-oC h CH [C ,H O;,], corresponding to a 6371 yield. Ni(O) (calculated): 6.8%; Found 6.6%; Total Ni (calculated): 6.8%; Found: 6.8%. An amount of 0.59 g. of unconverted nickel was recovered. Conversion of nickel powder to zerovalent nickel complex was 80%.

The effect of using even smaller amounts of initiator in the in situ preparation of the catalyst for the above reaction is illustrated in the following experiments. In these a 125 ml. flask was charged with 1.0 g. of nickel powder (prepared by hydrogen reductionof nickel oxide). 20 ml. of o-TTP. 10 ml. of acetonitrile. 1.0 g. of maleic anhydride and the amounts or TiCL, (microliters) shown in the table below. The mixture was stirred under nitrogen for 36 hours at 65C. and was then worked up described above. The results are shown in tabular form below.

Catalyst Total Ni Ni(O) Exp. TiCl, (mprh)'*' (Wt. (Wt. '71) v 1 3 1 1000 1.87 1.42. 2 0.3 100 1.25 g 194 3 "0.03 10 Q14 .13

*Moles per i'nillion moles based on weight o1 phosphorus ligand v ,EXAMPLE6- i i v ACRY LON1TR1LE[BIS(OLTRITOLYLPHOST PHITEHNICKELKQ) Following the procedure of Example 5, .1 reaction mixture of 1.0 g. nickel powder, 20 ml. of o-TTP."10 ml. of acetonitrile and 0.05 g. of iodine was stirred for different time periods a 20C.. samples were withdrawn and analyzed. The results were as follows:

An infrared analysis of a solution of the reaction mixture prepared as described above showed an absorption band at 2200 cm", corresponding with that of an authentic sample of acrylonitrile [bi s( tri-o-tolylphosphite)]nickel (O).

, EXAMPLE7- I FUMARON1TR1LE[B1S(TR1-O-TOLYLPHOS- PHITEHNICKEL 0;

EXAMPLE 8 ETHYLENE[ BlS(TRl-O-TOLYLPHOSPHlTE NICKEL (O) A 10 ml. pressure tube was charged with 0.5 g. of nickel powder. 3 ml. of o-TIP. 1.5 m1. of acetonitrile and 0.04 of TiBr The tube was pressured with 1000 atmospheres of ethylene, heated at 65C. for 16 hours after which the tube contents were worked up and analyzed. Zerovalent nickel was found to be 0.1%.

The preparation of the required catalyst used for the synthesis of the zerovalent nickel complexes from elemental niekelis also illustrated in Examples 9-] 1.

EXAMPLE 9 TlCL WlTl-l O-TRITOLYL PHOSPHITE EXAMPLE 10 zRci. WITH O-TRITOLYL PHOSPHlTE Zirconium tetrachloride (0.12 g. 0.0005 mole) was added to 3 g. (0.008 mole) of o-TTP. The mixture was heated to effect solution of the ZrCl after which the mixture was held at 94C. for 30 minutes. Analysis of the mixture by P NMR showed an area ratio of (o- CH,,C H O) PCl/ o-TFP of l/4.7, compared with a theoretical. area ratio of 1/3 ifall the Z rCl had reacted.

- HFCL; WITH O-TRITOLYL EXAMPLE ll v PHOSPHITE v Hafnium tetrachloride (0.16 g. 0.0005 mole) was added to 3 g. (0.008 mole) of o-TTP, the mixture was heated to effect solution of HfCl and thereafter held at 94C. for 30 minutes. Analysis by "P NMR showed a o-CH,,C H O) PCL/ o-TTP area ratio of H105, compared with a theoretical area ratio of l/3 if all HfCl had reacted.

PHOSPHITE)NICKEL(O) AND MALEIC ANHYDRIDE [BlS(TRl-M & P-TOLYL PHOSPHITEHNICKEUO) To'a 125 ml. flask there was charged and mixed under nitrogen at 25C. one gram of lNCO chemical grade nickel powder.- two grams of maleic anhydride, 20 grams 3-pentenenitrile and 12 grams of mixed metaand paratritolyl phosphite containing an estimated 800 ppm of (m 8L pCH C H.;O) PCl based on the weight of the tritolyl phosphite. Mixing under nitrogen was continued for 46 hours. at which time a sample removed for analysis showed 1.29 weight percent of nickel(O), corresponding to a 4471 conversion of nickel powder to zerovalent nickel in solution. On further mixing to a time of H5 hours analysis showed 1.81 weight percent of nickel(O). corresponding to a 6l7c conversion of nickel powder to zerovalent nickel in solution. Analysis by "P NMR showed both Ni[P(Om & p-C H CH and Ni[P(O-m & pC H CH [C H O5*] to be present.

*CIHLO;X maleic anhydride The experiments summarized in Table I further illustrate the insitu preparation of the required catalyst for synthesis of the zerovalent nickel complexes from elemental nickel.

In Table l the following abbreviations are used: PTTP, tri-ptolyl phosphite; OTTP. tri-o-toyl phosphite; TTP, mixed tri-metaand para-tolyl phosphites; 3PN, 3-pentenenitrile; ADN, adiponitrile; MON, 2- methylglutaronitrile; cyane, cyclohexane. In all of the experiments the amount of finely-divided nickel used was one gram, except in Experiment 25 wherein the designation (a) refers to the fact that the amount used was 1.5 grams. The designation (b) noted in some of the experiments refers to a unit of volume equivalent to one microliter (0.00l ml.).

TABLE I SYNTHESIS WlTH IN SlTU PREPARED CATALYST PZ; Ligand Metal Halide Solvent Temp. Time Conversion Exp. (g) (g) (ml) (hr 0 l PTTP. 7.0 NiCI 0.2 CH;,CN- 25 Reflux 16 72.4 2 NiBl 0.03 l6 76.3 3 NiL. 0.04 16 85.2 4 (C. ,H P. 4.0 NiCl 0.02 21 57.8

' 7 PTTP. 7.0 0.02 3PN 100 20 20.0 x g f ADN 16 9.2 9 nC,H,,CN Reflux 16 34.9 MGN I00 [6 22.l H p 3 0.05 CH CN l0 Reflux 21 46.8

Dioxanc I0 l2 l0 0.02 CH CN, l0 2| 34,8

\ Cyane. l0 l3 20 NiCl- 0.02 3PN. 10 l 10 22 11.3

CaCI 0.02 14 NiCl 0.05 JPN. I0 I00 22 4l.l

l.iCl 0.02 l5 NiCl 0.05 100 22 33 zncl 0.05 lo 7.0 l.iCl. 0.03 LH CN 25 Reflux I7 445 H- 10(h) l7 Kl CH CN. 25 18 29.4

l8 (.aCl- 002 C H CN. 25 I5 40.8

TABLE I -eontinued SYNTHESIS WITH lN SITU PREPARED'CATALYST PZ Ligand 1 Metal Halide Solvent Temp. Time Conversion. Exp. (g) (g) (ml) 1C) (hrs) v 20 1 3 se ci wmz -7 4519'- 21 CeCl 0.04 22 47.1 2 PTTP 7. 1 T1c1.,. 0.02 20 79.4 1 23 Y Tic1...15 b 20 110.9 24 TTP. 7.0 V 002 1' I r 7. 54.7 25"" PTTP. 14.0 CrC1.,.THF.0.04;- 50' 45.5 26 i PTTP. 7.0 MnCl 0.02 CHQCN 20 5.0 27 TTP RCCi 0.04 21 53.4 2s FCCI 0.02 20 3l.6' 2 FeCL 20 50.3 I 30 TTP. 7.0 RuCl 0.05 1' 15 23.8 31 Ruci sHgo. 20 37.2 i 32 PTTP 7.0 CoCl. 0.02 20 12.6 Y 33 TTP RhCl... 0.04 19 50.7 34 P11C1. 19 44.1 35 PTTP CuCl. 0.02 20 71.5 36 TTP AgCl. 0.04 20 53.7 37 Z110 0. 10 19 13.5 32 CdCl. 0.03 20 9.0 39 Hg. ,Cl. 0.05 20 68.2 40 H cl 20 74.9 41 TTP, 7.0 AlCl;, 0.02 CH;,CN 25 20 79.7 42 ThCl 0.04 21 48.4 43 51161... 0.04 20 5.9 44 SnCl 0.05 20 50.1 45 P0 20 0) 10 36.3 45 PCl 0.03 16 70.3 47 shC1,, 30111 21 43.4 45 1. 0.05 10 (78.8 49 HC]. 2111b) 25 53.0 50 50 0... 30 1) 0 3x7 51 C -,H;,N.HBr. 0.02 21 54.9 52 C -,H,,N.HC1 0.02 22 35.5 53 10 N1C1. CH..C1\1 10 21 14.1

C,,H .,N 10

EXAMPLE 54 We claim:

The preparation of zcrovalent complexes of the type Ni(MZ;1) wherein the R radicals of a given M2 ligand are different is illustrated in the several runs of Example 54.

In this example the ligands were triaryl phosphites wherein the R radicals of a given ligand were o-tolyl and phenyl groups.

The required triaryl phosphites were prepared by reacting phosphorus tricnloride with a specified mixture ofo-cresol and phenol previously dried over a moleclar sieve. heating the mixture overnight at 100C. heating the mixture at 200C. with a nitrogen purge to remove by-product hydrogen chloride for a further period of 4 to 6 hours or until the chloride level reached a required or desired level.

For preparation of zerovalent nickel complexes from the mixed triaryl phosphite, the mixed triaryl phosphite 100 g) was reacted with 3 g. of nickel powder (lnco Chemical Grade) and 40 g. of 3-pentenenitrile, the mixture being heated for three hours at C. and then held at 35C. for l6l8 hours. The results obtained with triaryl phosphites prepared with varying amounts of o-cresol and phenol are shown in tabular form below.

Phosphite Preparation 1. A process for the preparation of a zerovalent nickel complex of the group consisting of Ni( MZ;,) and Ni( MZ A wherein M is of the group consisting of P. As and Sb, Z is R or OR, R is an alkyl or aryl radical having up to 18 carbon atoms, at least one Z is OR and the R radicals of a given MZ may be the same or different wherein A is a monoolefinic organic compound with no other carbon-carbon unsaturation and having from 2 to .20 carbon atoms.

which comprises reacting elemental nickel with a ligand MZ wherein M and Z are as defined above at a temperature in the range of 0C.l 50C. in the presence of at least 5 moles per million moles,-

based on amount of the ligand, of a catalyst compound of the formula (R'O) R" .,MX wherein M is defined as above, R and R are alkyl or aryl radicals having up to l8 carbon atoms, and may be the same or different;

wherein x and 3 have a value of 1-2, y is O or 1, the

sum of x. y and z is 3; and X is a halide of the group consisting of -Cl, --Br and l, and wherein for the preparation of Ni(MZ;,)- A there is also present a monoolefinic organic compound A.

2. The process of claim 1 wherein the reaction is carried out at a temperature in the range of 25l00C. and in the added presence of an organonitrile.

3. The process of claim 2 wherein the zerovalent nickel complex is of the formula Ni(PZ;,)

4. The process of claim 3 wherein P2 is a triaryl phosphite.

5. The process of claim 4 wherein the triaryl phosphite is of the group consisting of triphenyl phosphite. tri-p-tolyl phosphite. tri-m-tolyl phosphite and tri(m & p-tolyl) phosphitc.

6. Theprocess of claim 2 wherein the catalyst compound (RO),R ,MX is prepared in situby introducing into-thereaction mixture an initiator. the initiator being-of the group consisting of halides of P. As and Sb. alkyl substituted halide of P, As and Sb, a halide of a metal. elemental halogen of the group consisting of C1 Br and-l and their corresponding hydrogen and thionyl halides.

7. The process of claim 6 wherein the initiator is of the group consisting of PX TiX ZrX HfX, and HX wherein X is a Cl, Br or l, and I 8. The process of claim 2 wherein the zerovalent nickel complex has the formula Ni(PZ,-;). ,A, wherein the R radicals are so chosen that for a given PZ;, the cone angle is at least l30 and wherein A is a monoolefinic compound with no other carbon-carbon unsaturated having from 2 to carbon atoms.

9. The process of claim 8 wherein A is a monoolefinic organiccompound with a strong electronegative group conjugated with the olefin carbon-carbon double bond.

10. The process of claim 9 wherein the monoolefinic organic compound is of the group consisting of maleic anhydride. acrylonitrile and fumaronitrile.

II. The process of claim 10 wherein P2 is of the group consisting of tri-o-tolyl phosphite. tri-ophenylphcnyl phosphite, tri-2,5-xylyl phosphite and tri- 2 4x ylyl phosphite.

l2. Theprocess of claim 11 wherein the catalyst compound (RO) .R,,MX is prepared in situ by introducing into the reaction mixture an initiator of the group consisting of PX TiX ZrX HfX and HX wherein X is Cl, Br or l and l 13. The process of claim 3 wherein the R radicals of a given P2 are different and at least one R is an o-tolyl radical.

14. The process of claim 13 wherein the R radicals other than o-tolyl are of the group consisting of phenyl, m-tolyl and p-tolyl radicals. 

1. A PROCESS FOR THE PREPARATION OF A ZEROVALENT NICKEL COMPLEX OF THE GROUP CONSISTING OF NI(MZ3)4 AND NI(MZ3)2A WHEREIN M IS OF THE GROUP CONSISTING OF P AS AND SB Z IS R OR OR R IS AN ALKYL OR ARYL RADICAL UP TO 18 CARBON ATOMS AT LEAST ONE Z IS OR AND THE R RADICALS OF A GIVEN MZ3 MAY BE THE SAME OR DIFFERENT WHEREIN A IS A MONOOLEFINIC ORGANIC COMPOUND WITH NO OTHER CARBON-CARBON UNSATURATION AND HAVING FROM 2 TO 20 CARBON ATOMS, WHICH COMPRISES REACTING ELEMENTAL NICKEL WITH A LIGAND MZZ WHEREIN M AND Z ARE AS DEFINED ABOVE AT A TEMPERATURE IN THE RANGE OF 0*C-150*C IN THE PRESENCE OF AT LEAST 5 MOLES PER MILLION MOLES, BASED ON AMOUNT OF THE LIGAND, OF A CATALYST COMPOUND OF THE FORMULA (R''O)XR"YMXZ WHEREIN M IS DEFINED AS ABOVE R'' AND R" ARE ALKYL OR ARYL RADICALS HAVING UP TO 18 CARBON ATOMS AND MAY BE THE SAME OR DIFFERENT, WHEREIN X AND Z HAVE A VALUE OF 1-2 Y IS O OR 1 THE SUM OF X, Y AND Z IS 3 AND X IS A HALIDE OF THE GROUP CONSISTING OF -CI-B AND -1 AND WHEREIN FOR THE PREPARATION OF NI(MZ3)2A THERE IS ALSO PRESENT A MONOOLEFINIC ORGANIC COMPOUND A.
 2. The process of claim 1 wherein the reaction is carried out at a temperature in the range of 25*-100*C. and in the added presence of an organonitrile.
 3. The process of claim 2 wherein the zerovalent nickel complex is of the formula Ni(PZ3)4.
 4. The process of claim 3 wherein PZ3 is a triaryl phosphite.
 5. The process of claim 4 wherein the triaryl phosphite is of the group consisting of triphenyl phosphite, tri-p-tolyl phosphite, tri-m-tolyl phosphite and tri(m & p-tolyl) phosphite.
 6. The process of claim 2 wherein the catalyst compound (R''O)xR''''yMXz is prepared in situ by introducing into the reaction mixture an initiator, the initiator being of the group consisting of halides of P, As and Sb, alkyl substituted halide of P, As and Sb, a halide of a metal, elemental halogen of the group consisting of Cl2, Br2 and I2 and their corresponding hydrogen and thionyl halides.
 7. The process of Claim 6 wherein the initiator is of the group consisting of PX3, TiX4, ZrX4, HfX4 and HX wherein X is a -Cl, -Br or -I, and I2.
 8. The process of claim 2 wherein the zerovalent nickel complex has the formula Ni(PZ3)2A, wherein the R radicals are so chosen that for a given PZ3 the cone angle is at least 130* and wherein A is a monoolefinic compound with no other carbon-carbon unsaturated having from 2 to 20 carbon atoms.
 9. The process of claim 8 wherein A is a monoolefinic organic compound with a strong electronegative group conjugated with the olefin carbon-carbon double bond.
 10. The process of claim 9 wherein the monoolefinic organic compound is of the group consisting of maleic anhydride, acrylonitrile and fumaronitrile.
 11. The process of claim 10 wherein PZ3 is of the group consisting of tri-o-tolyl phosphite, tri-o-phenylphenyl phosphite, tri-2,5-xylyl phosphite and tri-2,4-xylyl phosphite.
 12. The process of claim 11 wherein the catalyst compound (R''O)xR''''yMXz is prepared in situ by introducing into the reaction mixture an initiator of the group consisting of PX3, TiX4, ZrX4, HfX4 and HX wherein X is -Cl, -Br or -I and I2.
 13. The process of claim 3 wherein the R radicals of a given PZ3 are different and at least one R is an o-tolyl radical.
 14. The process of claim 13 wherein the R radicals other than o-tolyl are of the group consisting of phenyl, m-tolyl and p-tolyl radicals. 